In my 20s, I met the most amazing salesperson: If a prospective buyer liked cigars and cognac, he would show up in cowboy boots with a drink and a smoke — whatever it took to get the order. And he usually did.

Still, those behaviors often made their way into the workplace. He got so good at blending in to get what he needed from people that we never knew when he was being authentic or just trying to achieve his own ends. Of course, being a chameleon in the workplace can be positive if their goals align with those of the company. On the other hand, it can also spread toxicity.

While happy employees make happy companies, working in toxic environments can cause employees serious mental and physical harm. According to the National Alliance on Mental Illness, the decline in productivity as a result of depression and anxiety in the workplace costs the global economy $1 trillion and Americans $192.3 billion in lost earnings a year.

While the biggest risk comes from toxic leadership, even one toxic individual on a team can spread to others and, eventually, the entire company. At that point, the time and effort required from everyone affected to draw it out and address it can become a massive undertaking. Instead, with a little planning and preventative measures, leaders can root out toxic behavior and keep workplaces healthy.

Related: 4 Small Signs That Your Company Culture Is Becoming Toxic

What makes a workplace toxic?

Toxic behavior can take many forms — abuse, manipulation, intimidation, mocking or threatening; blaming team members for personal shortcomings, marginalizing them or pitting them against one another. The most toxic environments are usually led by insecure individuals acting in self-interest over the well-being of others. Toxic leaders create subordinates who reflect that unhealthy relationship onto their people, and that toxicity can spread to entire departments.

Such toxic environments damage employee motivation and satisfaction, driving poor communication and a lack of commitment that hurts productivity. In a 2023 survey by Mental Health America, nearly 8 out of 10 workers felt workplace stress from toxic behaviors affected their mental health. The mental and physical harm of toxic workplaces, like headaches, high blood pressure, anxiety, depression and even post-traumatic stress disorder, all hinder performance. Worst of all, good people within the sphere of toxicity can be driven to quit to escape it.

Related: Who’s Responsible for a Toxic Workplace? If You Do Any of These 3 Things, Look in the Mirror.

Proactively keep workplaces safe

Leaders can prevent issues from becoming toxic by creating a safe environment where everyone can be their best. This involves clarifying roles and responsibilities, setting realistic expectations and allowing and encouraging people to think freely, make mistakes and improve.

Leaders should also be understanding when experiences outside the workplace impact our ability to work. Recently, a family member dealing with personal issues found themselves struggling to meet the responsibilities of their professional role. In a toxic environment, their boss might have lashed out, spreading toxicity and creating another toxic employee. Instead, their boss chose to be patient and gave them space to heal, and they returned to work grateful.

Of course, despite our best efforts, toxic behaviors can infiltrate even the safest environment. So, establish a plan of action to get at the source and root it out. Here are three ways to start:

1. Ask questions

When confronting potentially toxic situations, ask: Were individuals exhibiting toxic behaviors when we hired them or did they develop while they were part of our team? If the former, how can we revise our hiring process to account for it? If the latter, where do they struggle: with coworkers or customers; peers or superiors; and how can we help them?

Learn to evaluate communication style for signs of self-interest and insecurities. Are they speaking to learn, clarify and arrive at a resolution, or just to be right? Do they listen, process feedback and make improvements, or excuse, negate and dismiss? Were they respectful? Interrupting or dominating the conversation can be red flags of toxicity.

2. Draw out that last 10%

Leaders can only resolve toxic behaviors once they know about them, but so much goes on in a company that leaders are unable to see. Those under-the-radar behaviors going unchecked the longest can often cause the most damage. If the environment looks good on the surface, people might feel too uncomfortable bringing up problems that might disrupt that.

While most employees can easily start a conversation about 80% or 90% of issues, at our company, we aim to make them feel safe enough to offer that last 10% — those nagging conflicts that might include low-level toxic behaviors going unnoticed. To a certain extent, this requires a sustained pessimism about what might be under the surface. Still, constantly striving to uncover those concerns better assures our ability to sustain a healthy environment.

3. Fix what can be fixed, remove what can not

Not every toxic behavior indicates a bad apple. Even top contributors might exhibit the occasional toxicity and still be worth the effort to try and reach. More information about roles, responsibilities, company goals or culture might be all they need to clear up any confusion.

Have discussions and draw up improvement plans. Use examples they can understand and explain what needs to change in a way that allows them to engage in productive conversation. For repeat offenders who are unable to recognize their behavior as toxic, consider the value of removing them before their toxicity can spread.

Related: 5 Types of Toxic Employees and How to Deal With Them

Build a network of workplace champions

For individuals to feel safe enough to speak up about toxic behavior, leaders need a network of managers to champion those relationships. This takes self-awareness into the example we set and our ability to accept feedback and reflect. I consider my actions through the lens of others and, when unsure, I ask. Our step-down review policy allows me to go directly to team members who report to my direct reports, not to step on toes but for insight. In a toxic workplace, such a policy could cause insecurities and discomfort, but with proactive efforts to build mutual respect and a secure environment of workplace champions, we set the stage for healthy team dynamics and long-term organizational success.